mach.subproj/mach_subsystem_join.c

   1 /*
   2  * @OSF_COPYRIGHT@
   3  */
   4
   5 #include <string.h>     /* To get NULL */
   6 #include <mach/boolean.h>
   7 #include <mach/kern_return.h>
   8 #include <mach/rpc.h>
   9
  10 #if     0
  11 #       include <stdio.h>
  12 #       define debug(x) printf x
  13 #else
  14 #       define debug(x)
  15 #endif
  16
  17 /*
  18  *      Routine:        mach_subsystem_join
  19  *      Purpose:
  20  *              Create a new subsystem, suitable for registering with
  21  *              mach_subsystem_create, that consists of the union of
  22  *              the routines of subsys_1 and subsys_2.
  23  *
  24  *      Warning:
  25  *              If there is a big gap between the routine numbers of
  26  *              the two subsystems, a correspondingly large amount of
  27  *              space will be wasted in the new subsystem.
  28  */
  29 rpc_subsystem_t
  30 mach_subsystem_join(rpc_subsystem_t subsys_1,   /* First input subsystem */
  31                     rpc_subsystem_t subsys_2,   /* Second input subsystem */
  32                     unsigned int *num_bytes_p,  /* Size of output subsystem */
  33                     void *(*malloc_func)(int)   /* Allocation routine to use */
  34                 )
  35 {
  36         rpc_subsystem_t                 sp, subsys_new;
  37         int                             num_routines, num_args, num_bytes;
  38         int                             i, j;
  39         struct routine_arg_descriptor   *ap;
  40         struct routine_descriptor       *rp;
  41
  42         /* Make sure the two routine number ranges do not overlap:
  43          */
  44         if (subsys_1->start <= subsys_2->start && subsys_1->end > subsys_2->start
  45                                         ||
  46             subsys_2->start <= subsys_1->start && subsys_2->end > subsys_1->start)
  47                 return NULL;
  48
  49         /* Arrange that subsys_1 is the subsystem with the lower numbered
  50          * routines:
  51          */
  52         if (subsys_2->start < subsys_1->start ||
  53                                         subsys_2->end < subsys_1->end) {
  54                 /* Exchange the two input subsystem pointers: */
  55                 sp = subsys_2; subsys_2 = subsys_1; subsys_1 = sp;
  56         }
  57
  58         debug(("subys_join: Lower subsys: (%d, %d); Higher subsys: (%d, %d)\n",
  59                 subsys_1->start, subsys_1->end, subsys_2->start, subsys_2->end));
  60
  61         /*
  62          * Calculate size needed for new subsystem and allocate it:
  63          */
  64         num_args = 0;
  65         sp = subsys_1;
  66         do {
  67                 int     nr;
  68
  69                 nr = sp->end - sp->start;
  70                 num_routines += nr;
  71
  72                 for (rp = &sp->routine[0]; rp < &sp->routine[nr]; rp++) {
  73                         /* Make sure this routine is non-null: */
  74                         if (rp->impl_routine != NULL)
  75                                 num_args += rp->descr_count;
  76                 }
  77                 if (sp == subsys_2)
  78                         break;
  79                 sp = subsys_2;
  80         } while (1);
  81         num_routines = subsys_2->end - subsys_1->start;
  82
  83         /* A struct rpc_subsystem, which is just a template for a real
  84          * subsystem descriptor, has one dummy routine descriptor in it
  85          * and one arg descriptor, so we have to subtract these out, when
  86          * calculating room for the routine and arg arrays:
  87          */
  88         num_bytes = sizeof(struct rpc_subsystem) +
  89                     (num_routines - 1) * sizeof(struct routine_descriptor) +
  90                     (num_args - 1) * sizeof(struct routine_arg_descriptor);
  91
  92         debug(("subys_new: %x; #routines: %d; #args: %d; #bytes: %d\n",
  93                             subsys_new, num_routines, num_args, num_bytes));
  94
  95         subsys_new = (rpc_subsystem_t) (*malloc_func)(num_bytes);
  96         if (subsys_new == NULL)
  97                 return NULL;
  98
  99         /* Initialize the new subsystem, then copy the lower-numbered
 100          * subsystem into the new subsystem, then the higher-numbered one:
 101          */
 102
 103         subsys_new->subsystem = NULL;   /* Reserved for system use */
 104         subsys_new->start = subsys_1->start;
 105         subsys_new->end = subsys_2->end;
 106         subsys_new->maxsize = subsys_1->maxsize > subsys_2->maxsize ?
 107                                 subsys_1->maxsize : subsys_2->maxsize;
 108         subsys_new->base_addr = (vm_address_t)subsys_new;
 109
 110         /* Point ap at the beginning of the arg_descriptors for the
 111          * joined subystem, i.e. just after the end of the combined
 112          * array of routine descriptors:
 113          */
 114         ap = (struct routine_arg_descriptor *)
 115                                 &(subsys_new->routine[num_routines]);
 116         rp = &(subsys_new->routine[0]);
 117
 118         /* Copy subsys_1 into subsys_new: */
 119         debug(("subys_join: Copying lower subsys: rp=%x, ap=%x\n", rp, ap));
 120         for (i = 0; i < subsys_1->end - subsys_1->start; i++, rp++) {
 121                 *rp = subsys_1->routine[i];
 122                 if (rp->impl_routine != NULL) {
 123                         rp->arg_descr = ap;
 124                         for (j = 0; j < rp->descr_count; j++)
 125                                 *ap++ = subsys_1->routine[i].arg_descr[j];
 126                 } else
 127                         rp->arg_descr = NULL;
 128         }
 129
 130         /* Fill in the gap, if any, between subsys_1 routine numbers
 131          * and subsys_2 routine numbers:
 132          */
 133         for (i = subsys_1->end; i < subsys_2->start; i++, rp++) {
 134                 rp->impl_routine = NULL;
 135                 rp->arg_descr = NULL;
 136         }
 137
 138         /* Copy subsys_2 into subsys_new: */
 139         debug(("subys_join: Copying higher subsys: rp=%x, ap=%x\n", rp, ap));
 140         for (i = 0; i < subsys_2->end - subsys_2->start; i++, rp++) {
 141                 *rp = subsys_2->routine[i];
 142                 if (rp->impl_routine != NULL) {
 143                         rp->arg_descr = ap;
 144                         for (j = 0; j < rp->descr_count; j++)
 145                                 *ap++ = subsys_2->routine[i].arg_descr[j];
 146                 } else
 147                         rp->arg_descr = NULL;
 148         }
 149         debug(("subys_join: Done: rp=%x, ap=%x\n", rp, ap));
 150
 151         *num_bytes_p = num_bytes;
 152         return subsys_new;
 153 }